“It’s not good enough for me, or anybody, to say, ‘Well, look, Republicans control the House: From Day One, we’re going to have to compromise,’ ” Sanders said in a Tuesday interview with The Washington Post.

“The Democratic Party, before they start compromising, has got to rally the American people around our ideas and make it clear that if Republicans do not go along with reasonable ideas to benefit the middle class and the working class, they are going to pay a very heavy political price.”

Sanders gave Clinton a major scare in the Democratic presidential primaries, winning 23 contests and 43 percent of the vote before endorsing Clinton, now the party's nominee, in July.

He used the leverage he gained in the primaries to influence the direction of the party’s platform, and on Tuesday he said his job would be “to demand that the Democratic Party implement that platform.”

“The leverage that I think I take into the Senate is taking on the entire Democratic Party establishment, and, you know, taking on a very powerful political organization with the Clinton people,” Sanders said.

“We won 22 states and 46 percent of the pledged delegates, 13.4 million votes ... and a majority of the younger people, the future of the country. ... That gives me a lot of leverage, leverage that I intend to use.”